1818486581 has 2 divisors, whose sum is σ = 1818486582. Its totient is φ = 1818486580.

The previous prime is 1818486529. The next prime is 1818486589. The reversal of 1818486581 is 1856848181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1159743025 + 658743556 = 34055^2 + 25666^2 .

It is an emirp because it is prime and its reverse (1856848181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1818486581 - 2²⁶ = 1751377717 is a prime.

It is a super-2 number, since 2×1818486581² = 6613786890554139122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1818486589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909243290 + 909243291.

It is an arithmetic number, because the mean of its divisors is an integer number (909243291).

Almost surely, 2^1818486581 is an apocalyptic number.

It is an amenable number.

1818486581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818486581 is an equidigital number, since it uses as much as digits as its factorization.

1818486581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 491520, while the sum is 50.

The square root of 1818486581 is about 42643.7167821943. The cubic root of 1818486581 is about 1220.5906351347.

The spelling of 1818486581 in words is "one billion, eight hundred eighteen million, four hundred eighty-six thousand, five hundred eighty-one".